Motivational effects on inhibitory control in children with ADHD.

OBJECTIVE

The problems children with attention-deficit/hyperactivity disorder (ADHD) encounter in tasks measuring inhibitory control are often theoretically related to deficits in cognitive processes. This study investigated the effects of different motivational incentives on the ability of children to inhibit intended or ongoing actions.

METHOD: In a large German industrial town, 33 children with ADHD were compared with 33 members of a combined group of children with major depressive disorder, anxiety disorders, oppositional defiant disorder, or conduct disorder, and 33 children without any psychiatric disorder with respect to their performances in a stop-signal task. The children received continuous feedback under high- or low-incentive conditions. The children's performance was compared in terms of qualitative (inhibition rate) and quantitative (reaction time) measures.

RESULTS

There were no indications of deficits in sustained attention in children with ADHD. Under conditions of low incentives, children with ADHD were less able to inhibit their reactions and had longer stop-signal reaction times. But when given high incentives, children with ADHD performed the task as well as both other groups.

CONCLUSIONS

Supposed deficits in children with ADHD should be regarded from a perspective that differentiates performance from ability. Furthermore, the findings support a motivational explanation of the origins of lowered inhibitory control in children with ADHD.